James Webb Space Telescope

Reading Time: 12 minutes


The curiosity about what was there 13.5 billion years ago and the search for the habitable planets might end. On 25th December 2021, NASA launched their massive 10 billion dollar endeavor, which will help humans look for what was there and what surprises the universe holds for us. The expensive James Webb Space telescope, simply called Webb, is named after James E. Webb, who served as the second administrator of NASA during the 60s and oversaw U.S. crewed missions throughout the Mercury and Gemini programs.

The JWST or Webb is a space telescope which is developed by NASA in collaboration with the European Space Agency and Canadian Space Agency. It will complement the Hubble space telescope and is optimized for the wavelengths in the infrared region. The JWST is 100 times more powerful than it. The diameter of the optical mirror of Webb is 6.5 meters making its collecting area 6.25 times more than Hubble. The Webb consists of 18 hexagonal adjustable mirrors made of gold-plated beryllium with just 48.2 grams of gold, about the same weight as a golf ball. Since the telescope is operating in the infrared region, the temperature around it needs to be very low to prevent the overwhelming of the sensors by the heat from the Sun, the Earth, and the heat emitted by its parts’. To overcome that the special material called Kapton with a coating of aluminum is used such that, one side facing the sun and earth would be around 85 degrees celsius while the other side would be 233 degrees Celsius below zero. Also, the problem of keeping the instrument’s temperature at an optimal level is solved by using liquid helium as the coolant. The telescope is going to have 50 major deployments and 178 release mechanisms for the smooth functioning of the satellite. The Webb was launched on Ariane 5 from Kourou in French Guiana and will take six months to become fully operational and is expected to work for 10 years.


The JWST project was being planned for 30 years and had to face many delays and cost overruns. The first planning was carried out in 1989 whose main mission was to “think about a major mission beyond Hubble”. There were many cost overruns and project delays throughout the making of the telescope. There were also many budget changes throughout the period. The original budget for making the telescope was going to be US$1.6 billion. Which was then estimated to be US$ 5 million by the time construction started in 2008. By 2010, the JWST project almost got shelved due to the huge budgets until November 2011 when Congress reversed the plan to discontinue JWST and set the cap of the funding at US$ 8 billion.


The telescope has been launched to study the early planets and galaxies formed after the Big Bang. The telescope would also help in finding out the formation of new planets and galaxies. The US Congress capped its funding to US$ 6 million.


Being an infrared telescope, the position of the telescope in space is crucial for its desired operation. The telescope has to be as far as possible from the sun so that the sun’s infrared ways don’t interfere with the telescope’s instruments as well as not being too far away from the earth to stay in contact with NASA all the time. So NASA decided to put the telescope in Lagrange point 2 of the sun-earth system. So the question arises what is a Lagrange point and what is its importance. Let’s go back and learn how Lagrange and Euler discover these points in space. The Lagrange points are points of equilibrium for small-mass objects under the influence of two massive orbiting bodies. Mathematically, this involves the solution of the restricted three-body problem in which two bodies are very much more massive than the third. These points are named after the French Italian mathematician and astronomer Joseph-Louis Lagrange who discovered the Lagrange points L4 and L5 in 1772 but the first 3 points were discovered by Swiss Mathematician and Astronomer Leonhard Euler in 1772.


Joseph-Louis Lagrange was an Italian mathematician and astronomer. He made significant contributions to the fields of analysis, number theory, and both classical and celestial mechanics. In 1766, on the recommendation of Swiss Leonhard Euler and French d’Alembert, Lagrange succeeded Euler as the director of mathematics at the Prussian Academy of Sciences in Berlin, Prussia, where he stayed for over twenty years, producing volumes of work and winning several prizes of the French Academy of Sciences. Lagrange’s treatise on analytical mechanics written in Berlin and first published in 1788, offered the most comprehensive treatment of classical mechanics since Newton and formed a basis for the development of mathematical physics in the nineteenth century

Lagrange was one of the creators of the calculus of variations, deriving the Euler–Lagrange equations for extrema of functionals. He extended the method to include possible constraints, arriving at the method of Lagrange multipliers. Lagrange invented the method of solving differential equations known as variation of parameters, applied differential calculus to the theory of probabilities, and worked on solutions for algebraic equations. In calculus, Lagrange developed a novel approach to interpolation and Taylor theorem. He studied the three-body problem for the Earth, Sun, and Moon (1764) and the movement of Jupiter’s satellites (1766), and in 1772 found the special-case solutions to this problem that yield what are now known as Lagrangian points. Lagrange is best known for transforming Newtonian mechanics into a branch of analysis, Lagrangian mechanics, and presented the mechanical “principles” as simple results of the variational calculus.


Normally, the two massive bodies exert an unbalanced gravitational force at a point, altering the orbit of whatever is at that point. At the Lagrange points, the gravitational forces of the two large bodies and the centrifugal force balance each other. This can make Lagrange points an excellent location for satellites, as few orbit corrections are needed to maintain the desired orbit. L1, L2, and L3 are on the line through the centers of the two large bodies, while L4 and L5 each act as the third vertex of an equilateral triangle formed with the centers of the two large bodies. L4 and L5 are stable, which implies that objects can orbit around them in a rotating coordinate system tied to the two large bodies. Now the magic of L2 point is that it is behind the earth and the sun thus if we want to view the night sky without the earth’s intervention when can do it from this point and since it is in the Lagrange point it is orbiting in the same speed as the earth so it can be in continuous communication with the earth through the Deep Space Network using 3 large antennas on the ground located in Australia, Spain, and the USA and can uplink command sequence and downlink data up to twice per day and use minimal fuel to stay in the orbit thus increasing the lifespan of the mission.


The telescope is going to be 1.5 million km away from the earth and will circle about the L2 point in a halo orbit, which will be inclined with respect to the ecliptic, have a radius of approximately 800,000 km, and take about half a year to complete. Since L2 is just an equilibrium point with no gravitational pull, a halo orbit is not an orbit in the usual sense: the spacecraft is actually in orbit around the Sun, and the halo orbit can be thought of as controlled drifting to remain in the vicinity of the L2 point. It will take the telescope roughly 30 days to reach the start of its orbit in L2.


Unlike the Hubble telescope which can be easily serviced in case of damage, the James Webb Space Telescope cannot be repaired/serviced due to its significant distance(1.5 million km) from earth even more than the most distance traveled by the astronauts during the Apollo 13 mission in which they traveled to the far side of the moon which is approximately 400,000 km from earth. Therefore this is one of the riskiest missions in human history with 344 single points failure could lead to the end of the mission and years of research and hard work of thousands of scientists down the drain.




NIRCam (Near-infrared camera) is an instrument that is part of the James Webb Space Telescope. The main tasks of this instrument include first as an imager from 0.6 to 5-micron wavelength, and second is as a wavefront sensor to keep 18 section mirrors functioning as one. It is an infrared camera with ten mercury-cadmium-telluride (HgCdTe) detector arrays, and each array has an array of 2048×2048 pixels. Also, NIRCam has coronagraphs which are normally used for collecting data on exoplanets near stars. NIRCam should be able to observe as faint as magnitude +29 with a 10000-second exposure (about 2.8 hours). It makes these observations in light from 0.6 (600 nm) to 5 microns (5000 nm) wavelength.



The main components of NirCam are coronagraph, first fold mirror, collimator Pupil imaging lens, senses, dichroic beam splitter, Longwave focal plane, Shortwave filter wheel assembly, Shortwave camera lens group, Shortwave fold mirror, Shortwave focal plane



NIRCam is designed by the University of Arizona, company Lockheed Martin, and Teledyne Technologies, in cooperation with the U.S. Space Agency, NASA. NIRCam has been designed to be efficient for surveying through the use of dichroic.



The Near Infrared Camera (NIRCam) is Webb’s primary imager that will cover the infrared wavelength range of 0.6 to 5 microns. NIRCam will detect light from the earliest stars and galaxies in the process of formation, the population of stars in nearby galaxies, as well as young stars in the Milky Way and Kuiper Belt objects.  NIRCam is equipped with coronagraphs, instruments that allow astronomers to take pictures of very faint objects around a central bright object, like stellar systems. NIRCam’s coronagraph works by blocking a brighter object’s light, making it possible to view the dimmer object nearby – just like shielding the sun from your eyes with an upraised hand can allow you to focus on the view in front of you. With the coronagraphs, astronomers hope to determine the characteristics of planets orbiting nearby stars.

James Webb Space Telescope



The NIRSpec (near-infrared spectrograph) is one of the four instruments which is flown with the James Webb space telescope. The main purpose of developing the NIRSpec is to get more information about the origins of the universe by observing the infrared light from the first stars and galaxies. This will also help in allowing us to look further back in time and will study the so-called Dark Ages during which the universe was opaque, about 150 to 800 million years after the Big Bang.



Coupling optics, fore optics TMA, calibration mirror 1 and2, calibration assembly, filter wheel assembly, refocus mechanism assembly, micro shutter assembly, integral field unit, fold mirror, collimator TMA, grating wheel assembly, camera TMA, focal plane assembly, SIDECAR ASIC, optical assembly internal harness.



Micro shutters are tiny windows with shutters that each measure 100 by 200 microns, or about the size of a bundle of only a few human hairs. The micro shutter device can select many objects in one viewing for simultaneous high-resolution observation which means much more scientific investigation can be done in less time. The micro shutter device is that it can select many objects in one viewing for simultaneous observation and it is programmable for any field of objects in the sky. The micro shutter is a key component in the NIRSpec instrument. Micro shutter is also known as arrays of tiny windows.


James Webb Space Telescope



The fine guidance sensor (FGS) is a typical instrument board on a James Webb space telescope, this provides high precision pointing information as input to the telescope’s attitude control systems. FGS provides input for the observatory’s attitude control system (ACS). During on-orbit commissioning of the JWST, the FGS will also provide pointing error signals during activities to achieve alignment and phasing of the segments of the deployable primary mirror.



THE FGS don’t have that much complex structure. so the following are the main components of FGS:- The large structure housing a collection of mirrors, lenses, servos, prisms, beam-splitters, photomultiplier tubes.



The FGS has mainly three functions in which this instrument was planted in our telescope:

1) TO obtain images for target acquisition. Full-frame images are used to identify star fields by correlating the observed brightness and position of sources with the properties of cataloged objects selected by the observation planning software

2) Acquire pre-selected guide stars. During acquisition, a guide star is first centered in an 8 × 8 pixel window.

3)  Provide the ACS with centroid measurements of the guide stars at a rate of 16 times per second.




James Webb Space Telescope
James Webb Space Telescope


The mid-infrared instrument is used in the detection process of the James Webb Space Telescope. Uses camera as well as a spectroscope, in detection helps in detection from 5 microns to 28 microns of radiation to observe such a large range of wavelength we use Detectors made up of Germanium doped with arsenic these detectors are termed as Focus plane modules and have a resolution about 1024 X 1024 pixels. The MIRI system needs to be cooler than other instruments to measure such a long wavelength range and provided with cryocoolers which consist of two elements i.e. pulse tube precooler and Joule Thompson loop heat exchanger to cool down the MIRI to 7 K while operating. Consists of two types of spectroscopes 


  • Medium Resolution Spectroscope- it is the main spectroscope that uses Dichroic and Gratings.

  • Low-resolution Spectroscope- it helps in slitless and long-slit spectroscopy with the help of double prisms to get the spectrum from range 5 to 12 micrometer. Uses Germanium and zinc sulfide prisms to get the dispersion of light.

James Webb Space Telescope
James Webb Space Telescope


To observe faint heat signals the JWST must need to be extremely cold to detect those faint signals. Sunshield helps in protecting the telescope from heat and light from the sun as well as the heat of the observatory also helps in maintaining a thermally stable environment and helps in cooling to 50K. 

The sun shield is made up of a material named Kapton which is coated with aluminum and the two hottest plates facing the sun also have silicone doping to reflect heat and light from the sun. have high resistance and are stable in a wide range of temperatures. 

 The number of plates and shape of plates play an important role in the shielding process. Five layers are used to protect the telescope and the vacuum between each sheet acts as an insulating medium to heat. Each layer is incredibly thin and the layers are curved from the center. 

James Webb Space Telescope


Some quick facts regarding the JWST:

  • The Webb’s primary mirror is 6.5 meters wide. A mirror this large hasn’t been launched in space before.

  • It will help humans to understand the dark age before the time when the first galaxies were formed. 

  • As of now, the JWST is fully deployed in space and is in its cooldown to let its apparatus work at an optimum level. So let’s hold our breaths for the wonderful and exciting discoveries that are yet to come. 

Why do Rockets love to fail?

Reading Time: 8 minutes

Deepak Kumar
Propulsion Engineer, Dept. of Propulsion, STAR

“Rockets, they really don’t wanna work, they like to blow up a lot”


         – Elon Musk

If you take look at all the List of spaceflight-related accidents and incidents – Wikipedia , you’ll realize there have been countless failures. That the answer to “How many”.


Rockets can fail anytime. Moreover, a rocket isn’t a simple machine at all. A massive structure having around 2.5 billion dynamic parts is likely to fail anytime if any of these parts says, “ I can’t do this anymore, I’m done”.


Coming to some of the well known Rocket Failures, this will help you learn how rockets fail!


1. The Space Shuttle Challenger Disaster

Why do Rockets love to fail?

The spaceflight of Space Shuttle carried a crew of 7 members, when it disintegrated over the Atlantic Ocean. The disintegration was caused due to the failure of one of Solid Rocket Boosters(SRB). The SRB failed during the lift-off.


The failure of SRB was caused due to O-Rings. O-ring is mechanical gasket that is used to create a seal at the interface. And here, that interface was between two fuel segments. O-Ring was designed to avoid the escaping of gases produced due to burning of solid fuel. But extreme cold weather on the morning of launch date, the O-Ring became stiff and it failed to seal the interface.

Why do Rockets love to fail?

This malfunctioning caused a breach at the interface. The escaping gases impinged upon the adjacent SRB aft field joint hardware( hardware joining the SRB to the main structure) and the fuel tank. This led to the separation of the Right Hand SRB’s aft field joint attachment and the structural failure of external tank.

Why do Rockets love to fail?

In the video below, the speaker mentions about the weather being chilly on that morning and icicles formed on the launch pad in the morning. One of SRB is clearly visible making its own way after the failure.

2. The Space Shuttle Columbia Disaster

Unlike the above failure, this failure occurred during the re-entry. But again, the story traces back to the launch. During the launch, a piece of foam broke off from the external fuel tank and struck the left wing of the orbiter.

Why do Rockets love to fail?

This is an image of orbiter’s left wing after being struck by the foam. The foam actually broke off from the bi-pod ramp that connects the orbiter and fuel tank.

Why do Rockets love to fail?

The foam hit the wing at nearly a speed of 877 km/h causing damage to the heat shield below the orbiter. The piece of foam that broke off the external fuel tank was nearly the size of a suitcase and could have likely created a hole of 15–25 cms in diameter.

Why do Rockets love to fail?

The black portion below the nose you see is the carbon heat shield of orbiter.

On Feb 1,2003 during the re-entry, at an altitude of nearly 70 km, temperature of wing edge reached 1650 °C and the hot gases penetrated the wing of orbiter. Immense heat energy caused a lot of dange. At an altitude of nearly 60 km, the sensors started to fail, the radio contact was lost, Columbia was gone out of control and the left wing of the orbiter broke. The crew cabin broke and the vehicle disintegrated.



You can clearly see the vehicle disintegrating. **The video is a big one, hang tight. 😉


3. The N1 Rocket Failure

Not many people know about this programme. It was started in 1969 by the Russians. N1 rocket remains the largest rocket ever built till date. The rocket had its last launch in 1972. During this tenure, the were four launches, all of them failed. Yes you heard it right, ALL OF THEM FAILED.

Why do Rockets love to fail?

Before discussing the failures, there is one thing that I never forget to mention about this rocket. Rockets rely on TVC(Thrust Vector Control) to change the direction of the thrust. The nozzle direction is changed to alter the direction of thrust.

Why do Rockets love to fail?

This is TVC. But in case of N1 Rocket, there was something called Static Thrust Vectoring. There were 30 engines in stage 1, 8 engines in stage 2, 4 engines in stage 3 and 1 in stage 4.

Why do Rockets love to fail?

There were 24 on the outer perimeter and the remaining 6 around the centre.

In order to change the direction of rocket, the thrust was changed in the engines accordingly. The engines didn’t move like TVC at all.

Now coming to the failed launches:

Launch 1:

The engines were monitored by KORD(Control of Rocket Engines). During the initial phase of flight, a transient voltage caused KORD to shut down the engine #12. Simultaneously, engine #24 was shut down to maintain stability of the rocket. At T+6 seconds, pogo oscillation( a type of combustion instability that causes damage to the engine) in the #2 engine tore several components off their mounts and started a propellant leak. At T+25 seconds, further vibrations ruptured a fuel line and caused RP-1 to spill into the aft section of the booster. When it came into contact with the leaking gas, a fire started. The fire then burned through wiring in the power supply, causing electrical arcing which was picked up by sensors and interpreted by the KORD as a pressurization problem in the turbopumps.

Launch 2:

Launch took place at 11:18 PM Moscow time. For a few moments, the rocket lifted into the night sky. As soon as it cleared the tower, there was a flash of light, and debris could be seen falling from the bottom of the first stage. All the engines instantly shut down except engine #18. This caused the N-1 to lean over at a 45-degree angle and drop back onto launch pad 110 East. Nearly 2300 tons of propellant on board triggered a massive blast and shock wave that shattered windows across the launch complex and sent debris flying as far as 6 miles (10 kilometers) from the center of the explosion. Just before liftoff, the LOX turbopump in the #8 engine exploded (the pump was recovered from the debris and found to have signs of fire and melting), the shock wave severing surrounding propellant lines and starting a fire from leaking fuel. The fire damaged various components in the thrust section leading to the engines gradually being shut down between T+10 and T+12 seconds. The KORD had shut off engines #7, #19, #20, and #21 after detecting abnormal pressure and pump speeds. Telemetry did not provide any explanation as to what shut off the other engines. This was one of the largest artificial non-nuclear explosions in human history.

Launch 3:

Soon after lift-off, due to unexpected eddy and counter-currents at the base of Block A (the first stage), the N-1 experienced an uncontrolled roll beyond the capability of the control system to compensate. The KORD computer sensed an abnormal situation and sent a shutdown command to the first stage, but as noted above, the guidance program had since been modified to prevent this from happening until 50 seconds into launch. The roll, which had initially been 6° per second, began rapidly accelerating. At T+39 seconds, the booster was rolling at nearly 40° per second, causing the inertial guidance system to go into gimbal lock and at T+48 seconds, the vehicle disintegrated from structural loads. The interstage truss between the second and third stages twisted apart and the latter separated from the stack and at T+50 seconds, the cutoff command to the first stage was unblocked and the engines immediately shut down. The upper stages impacted about 4 miles (7 kilometers) from the launch complex. Despite the engine shutoff, the first and second stages still had enough momentum to travel for some distance before falling to earth about 9 miles (15 kilometers) from the launch complex and blasting a 15-meter-deep (50-foot) crater in the steppe.


Launch 4:

The start and lift-off went well. At T+90 seconds, a programmed shutdown of the core propulsion system (the six center engines) was performed to reduce the structural stress on the booster. Because of excessive dynamic loads caused by a hydraulic shock wave when the six engines were shut down abruptly, lines for feeding fuel and oxidizer to the core propulsion system burst and a fire started in the boat-tail of the booster; in addition, the #4 engine exploded. The first stage broke up starting at T+107 seconds and all telemetry data ceased at T+110 seconds.

Besides the mechanical failures, the rockets might fail due to a minute discrepancy in program’s as in case of Ariane 5.

Ariane 5: After 37 seconds later, the rocket flipped 90 degrees in the wrong direction, and less than two seconds later, aerodynamic forces ripped the boosters apart from the main stage at a height of 4km. This caused the self-destruct mechanism to trigger, and the spacecraft was consumed in a gigantic fireball of liquid hydrogen.

The fault was quickly identified as a software bug in the rocket’s Inertial Reference System. The rocket used this system to determine whether it was pointing up or down, which is formally known as the horizontal bias, or informally as a BH value. This value was represented by a 64-bit floating variable, which was perfectly adequate.

However, problems began to occur when the software attempted to stuff this 64-bit variable, which can represent billions of potential values, into a 16-bit integer, which can only represent 65,535 potential values. For the first few seconds of flight, the rocket’s acceleration was low, so the conversion between these two values was successful. However, as the rocket’s velocity increased, the 64-bit variable exceeded 65k, and became too large to fit in a 16-bit variable. It was at this point that the processor encountered an operand error, and populated the BH variable with a diagnostic value.

That’s your answer to “why”. Rockets can fail anytime due even a small malfunction in one of those 2.5 billion dynamic parts or even a small programming error.

Hope you enjoyed the writings up there!

Thank You!

Source: Google and Wikipedia



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Seven new Worlds found by NASA

Reading Time: < 1 minuteMy blog is about the 7 new Earth-like planets found in a system that is 40 light years away (3.784×10^13 km) from us. You may be thinking that’s a pretty big distance but it’s not true in the case of astronomy. The star found is an ultra-cooled red dwarf about 9 % of Sun’s mass in Aquarius constellation named as Trappist-1. The seven planets orbit the star in the orbit that is much closer than Mercury’s orbit and a year on the closest planet Trappist-1b is only of 1.5 Earth days, while that of the farthest one Trappist 1h is only 18.8 Earth days. The planets pass so close to one another that gravitational interactions are significant.the size of all seven planets are more or less similar to that of Earth , all of them have chances of having liquid water on their surface and three of them that are Trappist 1(e,f,g) are in habitable zone making them the most appropriate place to be capable of sustaining life in the known universe besides Earth.

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